1. Field of the Invention
This invention concerns a method to anchor one foil to another foil in the production of multi-layer packs of circuits according to the so-called green-tape technology, as set forth in the main claim.
To be more exact, the anchorage method of this invention is carried out during the assembly of the green-tape foils before the compression step.
2. Discussion of Prior Art
The hybrid circuits of the so-called green-tape technology consist of thin foils of alumina in the raw state or of another like or analogous material, which have a printed circuit on one or both of their surfaces.
These green-tape foils are superimposed on one another in a number which may even amount to various tens of foils, and are compressed so as to produce a multi-layer element of a slender thickness.
The various components of the circuit in the single green-tape foils may be set in communication with each other through suitable connecting holes made in the green-tape foils and filled with a paste of a conductive material.
The anchorage operation of the state of the art is performed by applying an adhesive to the edges of each foil forming the green-tape circuit, so that the green-tape foils remain positioned and anchored together before the compression step is effected.
In this way any sliding of one foil in relation to another foil in the multi-layer pack of the green-tape circuit is prevented.
The above operation of anchorage by means of adhesives is performed by hand and involves considerable times and costs as well as a great number of rejects due to the inaccuracy of the application of the adhesives and to damage caused by manual handling.